Glucose Metabolism and Insulin Secretion in the Newborn Infant: Comparisons Between the Responses Observed the First and Seventh Day of Life to Intravenous and Oral Glucose Tolerance Tests

Abstract

Insulin secretion and glucose metabolism were studied during intravenous and oral glucose tolerance tests performed in one day and seven day old full-term and premature infants. Mean glucose disposal during the intravenous tests was more rapid in seven day old than in one day old infants.Insulin responses after intravenous glucose were characterized by higher insulin levels during the initial phase and lower levels during the second phase in both seven day old premature and full-term groups as compared with the patterns seen in one day < old infants. No differences in the mean values for blood glucose and plasma insulin were found among the four groups of infants at any time during the oral tests. DIABETES 23: 172-78, March, 1974. The low disposal rate of glucose administered intravenously in the newborn infant has been correlated with a reduced and delayed rate of insulin secretion. 1 " 6 However, it has been noticed that after the third day of life, the glucose assimilation coefficient (K t ) increases. 7 " 10 Since an increase in the pancreatic content and release of insulin in vivo (and in vitro in animals) has been observed in the immediate postnatal period, 1 1 ' 1 4 comparisons were made between insulin secretion in one day and seven day old full-term and premature infants. MATERIAL AND METHODSSubjects were 127 newborn infants: 36 one day old and 32 seven day old full-term infants and 27 one day old and 32 seven day old premature infants. Infants who were studied at one day of age were not restudied on the seventh day after birth, but groups of different infants were used. The mean birth weight of the fullterm infants was 3.41 kg. (range 2.96 to 4.05 kg.), and gestational age ranged from thirty-eight to forty weeks. The premature infants had a mean birth weight of 2.02 kg. (range 1.79 to 2.52 kg.), and their gestational age ranged from thirty-one to thirty-six weeks. The mean body weights were similar in the groups of premature infants. The tests were performed on the first day of life before any oral or intravenous feedings were started and, on the seventh day, on infants who had fasted for six hours. Infants of diabetic mothers, infants with hemolytic disease or other serious disorders and infants small for gestational age were not included in this study.Glucose tolerance was assessed with both intravenous and oral glucose tests. Intravenous glucose tolerance tests (IVGTT) were performed by rapid injection of glucose (1 gm./l kg. body weight/30 sec). The IVGTT was performed in 26 one day old full-term infants, 22 seven day old full-term infants, 15 one day old premature infants and 20 seven day old premature infants. Specimens of blood were taken at 0, 1, 3, 5, 10, 20, 30, 40, 60 and 90 minutes during the test for glucose and insulin determinations. Oral glucose tolerance tests (OGTT) were performed by administration of glucose in a dose of 2. 5 gm./l kg. body weight using a 40 per cent solution via nasogastric tube. The OGTT was performed in 10 one day old full-term infants, 10 seven day old full-te...

Enhanced insulin secretion and insulin sensitivity in young lambs with placental insufficiency-induced intrauterine growth restriction

“…To our knowledge, only a few studies in IUGR infants have investigated the early transition into neonatal life (24 to 72 h). Even though these studies associate small for gestational age (SGA) with glucose dysregulation, the results are inconsistent across studies, which might reflect a dynamic interaction between insulin sensitivity and insulin secretion (5,20,44,54). In sheep fetuses with placental insufficiency-induced IUGR, we have shown defects in pancreatic insulin secretion due to a reduced number of ␤-cells, but in vitro, fetal sheep islets (and, thus, individual ␤-cells) have increased insulin secretion capacity.…”

Endocrine and metabolic response in the human newborn to first feed of breast milk.

“…Several authors have investigated the response of the pancreatic endocrine cells in the perinatal period, both in the human and in animal studies in vivo and in vitro. The pancreatic-oc and the a-cells in mature infants respond to amino acids during the first day of life Williams et al, 1975), but there appears to be a change in the pattern of the plasma insulin response to glucose during the first week of life (Falorni et al, 1974). Lowy and Schiff (1968) showed that feeding on the first day of life in man did not increase urinary excretion of insulin, while Asplund (1972) concluded that in rats postnatal feeding was necessary for the ,-cell respons-s to mature.…”

Effect of Glucose Priming on Insulin Response in the Premature Infant

“…In both full-term and premature infants the disappearance rate of glucose from the blood is much slower than that in older infants, 20 and this low disposal has often been correlated with a reduced and delayed rate of insulin secretion. 816 However, the data of the present work do not seem to bear out this hypothesis.…”